Diaphragm for loud speakers



1,818,&54

Aug. 11, 1931. w. K. KEARSLEY DIAPHRAGM FOR LOUD SPEAKERS Filed Oct. 1,1926 ln'vent o r William K. Kearsleg,

by Hus Attorney.

Patented Aug. 11, 1931 UNITED STATES QENT WILLIAM K. KEARSLEY, OFSCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIC COMPANY, ACORPORATION OF NEW YORK i i DIAPHRAGM FOR LOUD SPEAKERS Applicationfiled October 1, 1926.

The present invention relates to sound reproducing devices of the typecommonly known as loud speakers, and more particularly to a form ofdiaphragm, suitable for loud speakers, which may be economicallyconstructed and which is adapted to faithfully reproduce sounds of bothhigh and low frequency.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims. My inventionitself, however, will best be understood from reference to the followingspecification, taken in connection with the accompanying drawings, inwhich Fig. 1 represents a view, partly in elevation and partly insection, of an assembled diaphragm and motor therefor; Fig. 2 is aperspective view of one section of the diaphragm and the centralsupporting cylinder therefor; while Fig. 3 is a front elevation of thesound reproducing device.

On my drawings I have indicated at 1 a magnet system comprising anannular pole piece 2 and a central core 3 provided with a winding 4. Ascrew threaded member 5 engages the end of the core 3 and has mountedthereon a pair of sleeves 6 and 7 which cooperate with member 5 tosecure in position two angular metal brackets 8 and 9. A stiff hollowpaper cylinder 10 is mounted to vibrate in the air gap between core 3and polepiece 2. The paper cylinder is maintained in position by meansof threads 11 85 and 12 which extend through the metal brackets 8 and 9andthe cylinder 10, as clearly indicated in Fig. 2. The threads preventlateral movement of the cylinder but permit movement thereof in an axialdirection. An actuating coil 13 is mounted on one end of cylinder 10 andis movable in the air gap between the core 3 and polepiece 2. A seriesof tubular members 14, constructed of paper, are radially mountedadjacent one another at the opposite end of cylinder 10 and arecompressed or flattened at their op-' posite ends to provide a rigidsurface with radially extending corrugations where the adjacent sides ofthe tubular members meet.

The tubes 14 may be secured to cylinder 10 Serial No. 138,982.

in any suitable manner, as by an adhesive. Since the surfaces of theflattened end portions of members 14 are substantially 90 displaced fromone another, a substantially flat diaphragm of great rigidity isprovided and at the same time the surface of the diaphragm issubstantially continuous with no gaps between adjacent tubes. Anadhesive may be applied at the line of contact of adjacent surfaces ofmembers let to give further rigidity if desired. The diaphragm as thusconstructed is movable as a whole "in an opening 15 of the container forthe loud speaker unit. No support is required at the outer edge of thediaphragm, and while the diaphragm is extremely light in weight, it has,nevertheless, owing to the form of the tubular members, suflicientrigidity to maintain its shape indefinitely.

hat I claim as new and desire to secure-7 by Letters Patent ofthe UnitedStates is:

1. A diaphragm comprising a hollow cylindrical member and series ofhollow tubular members radially mounted thereon forming thereby asubstantially continuous .75 surface.

2. A diaphragm adapted to be vibrated, said diaphragm comprising aseries of hollow members radially arranged about a cen tral axis andflattened at opposite ends thereof to thereby provide a substantiallycontinuous surface.

3. In a sound reproducing device, a diaphragm comprising a series oftubular members flattened at opposite ends thereof and mounted adjacentone another to thereby provide a substantially continuous surface. I

4. A diaphragm comprising a hollow cylindrical member, a series ofhollow tubular members mounted thereon and (Xi-s tending in radialdirections from the cylindrical member, each of said tubular membershaving lattened end portions displaced substantially 90 to therebyprovide a substantially continuous surface. 91)

5. A diaphragm comprising a hollow cylindrical member, a series ofhollow tubular members mounted thereon and extending in radialdirections from the cylindrical member, a stationary member, and aplural-

